1. Field of the Invention
The present invention relates to a method for manufacturing a circuit board used in electronic devices (e.g., various types of audio visual devices, home electronics, communication devices, computer devices, and peripheral devices thereof), and a method for manufacturing a mounting structure of the same.
2. Description of the Related Art
A mounting structure in which electronic components are mounted on a circuit board is conventionally used for the mounting structure in an electronic device.
Japanese Laid-Open Patent Publication No. 2009-277905 describes a method for manufacturing a circuit board including the steps of forming a seed layer on a base layer, forming a copper plated layer on the seed layer, obtaining a circuit layer by etching the seed layer using the copper plated layer as a mask, and roughening a surface of the circuit layer using an alkaline aqueous solution.
In the method for manufacturing the circuit board described in the above reference, if a resin layer containing polyimide resin is used as the base layer, the imide ring contained in the resin molecule of the polyimide resin exposed at the surface of the resin layer is easily hydrolyzed by the alkaline aqueous solution used to roughen the surface of the circuit layer. As a result, the carboxyl group is produced by such hydrolysis so that the conductive material of the circuit layer ionizes and bonds with the carboxyl group, whereby the insulation property easily lowers between the circuit layers. Therefore, the circuit layers are easily short circuited, and furthermore, the electrical reliability of the circuit board easily lowers.